I think the discussion is more focussing on is that 'flexibilty and convenience' from the car based on the fact we have designed and allocated our cities, suburbs and town in the way we have already.. Not so much, well this tool is right for the job, more a question of, did we make this job that requires a tool.
If you were the only person with a car, then all cities are more flexible and convenient with a car than without. It is only when somebody other than you has a car that you get gridlock and the other problems of cars.